This invention relates to a color image processing apparatus and, in particular, to a color image processing apparatus, such as a copying machine, which reads an original image and performs a predetermined processing.
A conventional copying machine is capable of automatically making a judgment as to whether an original it reads is a monochromatic or a color one. The judgment can be made by examining the R, G and B components of the individual pixel data constituting the read image data.
When the read original is a monochromatic one, copying is performed in black only, and, in the case of a color original, copying is performed in the three colors of yellow, magenta, and cyan, or in four colors consisting of the above three and black. Generally, when coping a color original with a copying machine that does not have a one page image memory and that uses only a single photosensitive drum, the number of scannings performed on the read original must correspond to the number of recording colors so that signals corresponding to the respective recording colors (yellow, magenta, cyan, and black) can be generated. In the case of a monochromatic original, however, copying is performed with a single scanning, thus attaining a reduction in copying time as well as a reduction in cost by not using recording materials of needless colors (ink, toner, etc.).
However, the above conventional apparatus has the following problem:
Since the above judgment presupposes an original having a white background, an original having a uniformly colored background will be judged to be a color original even when those portions thereof which constitutes the information, i.e., characters, figures, etc., are black. Thus, with this conventional image processing apparatus, an original which has been prepared by copying an image monochromatically on colored paper or yellowish recycle paper, will be treated as a color original, and is, color-copied when monochromatic copying is enough, resulting in a waste of copying time and cost.